My PC powers on, but the monitor often shows no signal during startup. Reseating the RAM and graphics card and reinstalling the CMOS battery did not help. At first, opening the BIOS menu seemed to make the display appear, but I later realized that pressing the case's reset button was what actually fixed it. The problem started suddenly; the computer worked normally the previous night. I'm using a Radeon 9070 XT and a Ryzen 7 9800X3D. I also tested booting without the graphics card, using the motherboard's DisplayPort output, and still got no signal. What could cause this, and how can I fix it without having to press reset every time?
2 Answers
The fact that pressing the case reset button is what restores the signal suggests the first boot attempt may be hanging or failing to complete hardware initialization. It would be useful to compare a cold boot after shutdown with a normal restart, since some firmware and memory-training problems only appear after a full power-off. Updating the motherboard BIOS, loading BIOS defaults, and testing with one RAM stick at a time would be reasonable next steps.
Since the same behavior happens with the dedicated GPU removed and the monitor connected to the motherboard, the graphics card itself is less likely to be the main cause. The system may be failing during POST or having trouble initializing video output. Check the motherboard’s diagnostic LEDs or error display while it starts, and try a full power drain before booting: shut it down, switch off the PSU, unplug it for a minute, then hold the power button briefly before reconnecting everything.
I originally thought opening the BIOS was fixing it, but I confirmed that the case reset button is what makes the display appear. I’ll check whether it only happens after a full shutdown or also after restarting.